"I'll be Joe Biden and I'll try to be the best Biden I can be," the 64-year-old Delaware lawmaker said. "If I can, I have a shot. If I can't, I lose."
Biden said he will set up an exploratory committee by the end of the month that will help him raise money and gauge support for his candidacy.
Biden, who long has made clear his intentions to seek the White House in the wide-open race, has about $3.5 million in his campaign account. He has campaigned extensively in early voting states such as New Hampshire, Iowa, South Carolina and Nevada.
"I am running for president," he said on "Meet the Press" on NBC. "I will file for an exploratory committee before the month is out."
Considered one of his party's most experienced spokesmen on international affairs, Biden is the new chairman of the Senate Foreign Relations Committee.
He plans a series of hearings on the Iraq war and has promoted a detailed plan for peace in Iraq that would divide the country along ethnic lines.
Biden's first presidential bid collapsed 20 years ago amid allegations he plagiarized a campaign speech from then-British Labor Party leader Neil Kinnock.